From: Luca BRUNO <lucab@lucabruno.net>
To: musl@lists.openwall.com
Subject: Re: [musl] musl resolver handling of "search ." in /etc/resolv.conf
Date: Fri, 2 Sep 2022 08:09:00 +0000 [thread overview]
Message-ID: <20220902080900.0291d2c8@ephyra> (raw)
In-Reply-To: <20220901180153.GB21934@brightrain.aerifal.cx>
On Thu, 1 Sep 2022 14:01:53 -0400
Rich Felker <dalias@libc.org> wrote:
> > From my observations, option 1 is consistent with other libc's
> > behavior. But it has the above caveat that it needs additional
> > caching to avoid duplicate root-queries on negative responses.
> > If it isn't too invasive to implement, that would be my preferred
> > one.
>
> I'm not clear what additional caching you have in mind. AFAICT the
> search loop can just set a flag if it searched root already, and the
> final root query can be skipped if it's reached and the flag is set.
Yes sorry, poor choice of wording from my side, that was the additional
logic I was hinting to.
For future reference, this bug was observed in the wild due to a
combination of recent systemd (>= v247) and kubernetes (= 1.25.0).
The on-host systemd behavior is on purpose, while the logic on
kubernetes side was not completely expected.
A bugfix for kubernetes is being assembled right now to avoid triggering
this case, see https://github.com/kubernetes/kubernetes/pull/112157.
But the same situation may crop up with other non-kubernetes runtimes,
if they try to blindly forward/merge the "search ." from the host
environment.
Ciao, Luca
next prev parent reply other threads:[~2022-09-02 8:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-31 17:33 Dalton Hubble
2022-08-31 23:59 ` Rich Felker
2022-09-01 1:32 ` Jeffrey Walton
2022-09-01 12:45 ` Rich Felker
2022-09-01 16:03 ` Luca BRUNO
2022-09-01 18:01 ` Rich Felker
2022-09-02 8:09 ` Luca BRUNO [this message]
2022-09-19 17:18 ` Rich Felker
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